Each year, more than 200,000 women are diagnosed with, and nearly 40,000 die from their breast cancer (BC). Previous literature shows that social determinants, such as social networks, the web of social relationships that surround an individual, have a major role in BC survival. However, the mechanisms through which social networks influence prognosis, particularly effects on BC treatment, are unknown. Also, there is currently no systematic way in clinical care to identify socially isolated BC patients to facilitat intervention. Dr. Kroenke's career goal is to become a multidisciplinary, independently funded academic researcher in the social environment and cancer outcomes, to determine points of leverage for augmenting social networks to optimize BC treatment and improve clinical outcomes. Career development goals are to develop knowledge and expertise in: 1) The social environment (including social network theory, measurement, and analysis); 2) The conduct of social network behavioral interventions; 3) Clinical BC treatment and the use of electronic medical records (EMR) in research; and 4) Professional research skills. Goals will be accomplished through work with an outstanding group of mentors; formal didactics; seminars; meetings; and conferences. Specific Aims (SA) include: 1) In the Pathways study, a large KPNC cohort of 4,505 BC survivors with extensive data on social factors and cancer treatment, evaluate associations of social networks and BC treatment; 2) Evaluate associations of social networks, BC recurrence and mortality and the extent to which treatment variation related to social networks explains associations with survival; and 3) Develop, pilot, evaluate, and refine a brief social networks as a vital sign (SVS) measure to be collected in BC patients at the KP Oakland Medical Center, for entry into the EMR. Linear regression and survival methods will be used to analyze associations with BC treatment including receipt of and time to treatment and adherence to adjuvant hormonal therapy, as well as survival outcomes. We expect that women with a greater degree of supportive ties, and greater density, strength, and diversity of ties, wil have earlier, and better, adherence to treatment, and that treatment variations will help explain associations with survival. Findings from SA 1-2 and the proposed training will provide the foundation for developing the SVS measure in SA 3. The proposed study is the first to examine how social network structure influences BC treatment and survival. KPNC is an ideal environment for this career development award given strong mentors, institutional commitment, unique and extensive data on social factors and treatment, physician interests in improving patient social support, and opportunities for clinical intervention. Results from this study will b used to identify individual patients with compromised social networks within a large managed health care system and develop individual and system-level R-level social network interventions to optimize treatment and prognosis. Translating results to KP nationwide may improve outcomes in up to 20% of BC patients among the 10,000 incident BC cases diagnosed in KP each year.